But, when this happens, customers don't expect to be left waiting
for hours just to find out what is going on. And when they complain
they should be taken seriously.

With some companies, as many as f ive out of six customers who complain are left unhappy with the service they receive.

Consumer group Which? says energy companies have the worst customer service of all industries.

And watchdog Consumer Focus receives more than 11,000 calls from worried energy customers every month.

Around a third of these come from customers who are trying to
make the energy companies take seriously their concerns over an
incorrect bill.

Meanwhile, the independent Energy Ombudsman, which intervenes
only when every possible avenue has been investigated, gets around
6,000 calls a month.

Money Mail is constantly bombarded with letters and emails
from readers complaining about energy companies. You tell us their
customer service staff:

Fail to correct bills when promised.

Fail to call off debt collectors when you are being chased without reason.

Refuse to let you lower your monthly direct debits.

Refuse to believe that meter readings they took are incorrect.

Make it difficult to get refunds when you have overpaid.

Ignore letters and emails.

Give no explanation as to how mistakes are made.

Don't call you back when promised.

Leave you on hold for hours.

Have complicated automated systems that force you to press dozens of buttons.

Yet while customers are left on hold these massive companies are
raking in million of pounds in profits. six giant suppliers provide gas
and electricity to 97 pc of all UK households: British Gas, Scottish
and Southern Energy, Scottish Power, E.on, EDF and NPower.

British Gas, with 15.7 million customers, saw profits increase
58 pc to £595million last year, while Scottish Power, owned by Spanish
power giant Iberdrola, made £1.3billion.

'We've been doing a survey of energy companies for two or three years and nothing has changed.

'They're not learning their lessons. They've got customers over a barrel, so they don't care how they treat them.'

Ofgem has promised a fresh investigation into customer service later this year.

Your rights

Most of the protection consumers get comes from Ofgem and powers
granted in various laws, including the Enterprise Act 2002 and
Utilities Act 2000.

Ofgem will investigate and can fine any energy supplier which has breached the customer service standards.

These basically protect you from being sold anything you don't
understand, need or isn't right for you. However, the most important is
the last one.

It states: 'Suppliers must make it easy for their customers to
contact them and act promptly and courteously to put things right when
they make errors.'

If the energy firm doesn't do this it is in breach of Ofgem rules: so tell them.

When you sign up to an energy company you will have to sign a
contract. This will include the standards of service they promise, such
as how often your meter will be read and how it will respond to
complaints and queries.

When these service standards are part of a contract the company is
legally bound to stick to them. So before you start any complaint grab
your original contract.

There is a voluntary code of practice for accurate bills that all
the energy companies, apart from Scottish & Southern, have
subscribed to.

This states an energy firm must try to read your meter at least every two years. If it can't, then it will ask you to do it.

The company is under no obligation to read your meter more regularly than this.

If you don't receive a bill for more than a year and it is the
company's fault then you don't need to pay debts outstanding from more
than 12 months previously.

However, if you've refused to pay or have prevented the company taking readings, then you will still have to pay up.

On top of this, the Limitations Act 1980 prevents you being
charged for gas or electricity used more than six years ago. In
Scotland it is five years.

The code of practice also states you should you get clear,
accurate, informative and timely bills and statements; support and
advice on monitoring energy consumption and contact details for raising
questions with suppliers.

How to complain

First complain to the energy company.

Consumer Direct will talk you through the complaints process and how to take your problem further.

If you are a vulnerable customer, such as someone with young
children in the house or who is disabled, you will be passed to
Consumer Focus, which will help with your complaint and make sure your
supply is not cut off.

The energy company has eight weeks to resolve the problem. You should be given a copy of its complaints procedure.

After that time, you can go to the energy Ombudsman, to sort it
out for you, on 0330 440 1624 or 01925 530 263. Or you can use the
online enquiry form available at www.enso.org or write to PO Box 966,
Warrington, WA4 9DF.

The Ombudsman should come to a conclusion within six weeks. If
you are not happy with the decision, you can go back with any further
information you feel is relevant. The service is free to you.

It can award you compensation up to £5,000 but this does not include billing errors.

The Ombudsman's decision is binding on the companies.

They have 28 days to put the situation right after you have accepted
the decision. If they don't, you can contact the Ombudsman's office
again. You always retain the right to take your case to court.

Rosemary Grayson

They set the debt collectors on me

Rosemary Grayson, 58, was chased by debt collectors from Scottish Power after switching to Utility Warehouse in November.

Mrs Grayson, of Corwen, North Wales, says: 'I didn't know whether my final reading was an actual reading or an estimated one and asked them to come back with details.

'Every time you phone, you spend 15 minutes or more holding on.

'Then a debt collector rang and demanded I pay £91 over the phone then and there or it may damage my credit rating. Had I been of a more timid nature I would have complied.

'I heard no more until I had my final bill on February 20, which showed I had paid in full. I rang to check I hadn't paid twice. I was treated in a patronising manner by someone who simply kept repeating what was on the bill and not using normal, understandable language.

'Their bills are misleading and impenetrable.'

A spokesman for Scottish Power says: 'We aim to deliver a first class customer service to all our customers. We apologise if Ms Grayson feels she did not receive this.'

I made 20 phone calls but British Gas wouldn't listen

Hugh and Liz Thompson

A nightmare of massive bills and interminable wrangles started when retired policeman Hugh Thompson, 56, and his wife Liz moved into their newly-built home near Newcastle-upon-Tyne in June last year.

The builders had their gas and electricity supplied by British Gas Business and the Thompsons decided to stay with the company for their domestic supply. But they received bills from both arms of British Gas.

Whenever Mr Thompson rang one to try to sort it out, he was told to ring the other. He says: 'They'd promise to sort it out but they never did.'

Two days before Christmas they received an 'urgent' bill for £741.27 from the business side with a £40 late payment charge and the threat of debt collectors.

In all, he made about 20 calls to British Gas.

Finally, at the end of January he emailed managing director Phil Bentley directly after seeing his address (phil. bentley@britishgas.co.uk) in Money Mail. A senior person was appointed to deal with him and it was sorted out in a week.

Mr Bentley also wrote to him saying: 'It certainly does look like we have tried to confuse and confound you at every turn. Please do accept my personal apologies for the unacceptably poor service you've encountered.'

My meters have been wrong since 2002

Software designer Jeremy Hall, 67, has been fighting with E.on for almost a year, after the company discovered the meter readings at his two-bedroom bungalow had been incorrect since 2002.

He has two meters: one for peak and the other for off-peak usage. In 2009, the company's systems picked up that the two meters had been on the wrong rate for seven years and switched them back without letting him know.

Then they billed him £500 for their mistake. The energy retailers Association, the industry body, has a back billing code which prevents this.

Mr Hall, who lives in Chorley Wood, Hertfordshire, says: 'It's incredible that they simply flipped the meters back without contacting me.

'I repeatedly phoned and emailed them asking for an explanation. They never answered these questions but I had to reply to them within seven days, otherwise they would assume the matter was closed.'

Instead, they asked him to read the meters himself.

Finally the back-payment was dropped, resulting in a refund, in October, of £644. He then complained to the energy Ombudsman-who awarded him £75 for 'customer service shortfalls' and an apology, but it criticised him for not providing meter readings.

A spokesman for E.on says: 'We have apologised for the mis-reading. We are sorry for not explaining how this happened and for not checking the meters further. We have agreed to fit a check meter to test their accuracy.'